1. Field of the Invention
The present invention provides a sound attenuation assembly for utilization with air-cooling apparatus. More specifically, the invention provides an assembly that is particularly adaptable for utilization on forced-draft, liquid-to-air cooling apparatus at either, or both, the air entry port or the air discharge port of the air cooling apparatus.
2. Prior Art
Forced-draft, liquid-to-air cooling systems utilize air moving machinery, such as fans, which generate noticeable or significant noise. This noise at a certain decibel level is unacceptable in commercial buildings, urban settings and specific geographic regions or environments, such as Europe and Japan. Sound deflection barriers and sound absorbing members, which are referred to as attenuators, may be installed in the air flow path.
Sound deflection barriers have limited application as they may disturb the aesthetic appearance of the building, structure or surroundings. In addition, these barriers have limited effect in reducing the noise level and frequently require structural reinforcements against the wind. The added barrier structures can increase the cost and the overall size of the cooling apparatus.
The most frequently utilized devices to suppress an elevated decibel level are the sound absorbing members or attenuators. For sound abatement purposes, the sound absorbing members may be positioned at either the air inlet or air outlet side, or both, of the liquid-to-air cooling system. An exemplary attenuator system includes an enclosure with rectangular baffles therein of a sound absorbing material. This attenuator system is interposed in the air flow path either upstream of the air inlet or downstream of the air outlet for transmission of the air stream through the enclosure and baffle network. Generally these baffles have a rectangular configuration of a material, such as fiberglass. However, the baffles and their associated structure tend to be bulky and expensive. Further, use of the rectangular baffles increases significantly the static pressure losses along the air flow path.
There are known sound absorption devices, which are mountable on or from ceilings and walls. However, these devices are considered to be relatively expensive in comparison to attainment of sound attenuation by means of a baffle and enclosure arrangement.